ORIGINAL: BuckMaster7
The .22 calibers are really .224" in diameter. The 30-06 has a longer range than a 30-30 because it has more powder. The 30 in 30-30 stands for how many grains of powder it has. The 06 in 30-06 is the year they chambered rifles in 30-06. The .30 calibers are really .308" in diameter. The .270 is really .277" in diameter. You find this a lot in the calibers.
Man, all I have to say is that this system needs some sort of standardization. It is kina confusing (and maddening).